1. Field of the Invention
The present invention relates to a light emitting device.
2. Description of the Related Art
Patent Reference 1 discloses a light emitting device, wherein a square-shaped flip chip of light emitting diodes and a square-shaped sub-mount are superposed with each other with their centers aligned with each other, and, at the same time, the flip chip is set rotated by 45° with respect to the sub-mount, and two lead-out electrodes are formed with respect to the flip chip on the upper surface exposed regions of the sub-mount.
Patent Reference 2 discloses a light emitting device, wherein a plurality of linear shaped wiring patterns are arranged parallel with each other on an insulating substrate, and it has a light emitting portion, wherein a plurality of light emitting elements are carried between the wiring patterns while they are electrically connected to the wiring patterns; and the light emitting portion is sealed by a sealing member.    Patent Reference 1: Japanese Patent No. 4296644    Patent Reference 2: JP-A-2008-227412
According to the invention described in Patent Reference 1, the area of the lead-out electrodes (external electrodes) is large on the square-shaped sub-mount (substrate), and the area of the flip chip is large, so that the light emitting region can also be made larger, making it possible to obtain a light emitting diode with a small size and a high luminance.
However, Patent Reference 1 discloses only the constitution using one flip chip.
Patent Reference 1 does not disclose or indicate the constitution that a plurality of flip chips is arranged in an overall square-shaped configuration and carried on a sub-mount.
Consequently, it is hard for the person skilled in the art to reach the idea of the constitution that a plurality of flip chips is arranged on the basis of Patent Reference 1.
According to the invention described in Patent Reference 2, the constitution has a nearly rectangular-shaped light emitting portion set rotated by 45° with respect to an insulating substrate (see FIG. 1).
However, Patent Reference 2 neither discloses nor indicates the constitution that the light emitting element is connected to the wiring pattern using wire bonding.
Also, Patent Reference 2 neither discloses nor indicates the constitution that the light emitting element is flip-chip bonded to the wiring pattern.
Consequently, it is hard for the person skilled in the art to reach the idea of the constitution using flip chip bonding on the basis of Patent Reference 2.
It is necessary to reduce the area of the substrate in order to miniaturize the size of the light emitting device.
Also, it is necessary to increase the size of the sealing region where a plurality of light emitting elements is sealed by a sealing member in order to increase the light emitting region.
Consequently, the outer peripheral edge of the sealing region and the external electrodes are arranged near each other. As a result, when solder is applied on the external electrodes, the solder and the solder flux corrode the sealing region and contaminate the sealing region. As the sealing region is contaminated, the luminance falls, and uneven light emission takes place, degrading the light emitting quality, which is undesirable.
In addition, in the manufacturing method wherein a sealing frame is formed on the outer peripheral edge of the sealing region and a sealing material is injected into the interior of the sealing frame, the sealing frame is prone to deformation so that it may easily shift outward. As a result, the sealing frame cannot work normally, and sealing may be impossible to perform, or the sealing region may deform, leading to degradation in the light emission quality, which is undesirable.